Various methods and devices for locating and fitting a ring, a hub or the like to a shaft are known. A particularly difficult problem in this regard is to secure a ring member which is to be pretensioned to a certain axial preload. This is required, for example, in connection with taper roller bearings, although the method is not limited to the fitting of rings, and the problem then is momentarily to lock the ring axially and radially, at the moment the ring has obtained exactly the required or desired preload, without the ring thereby or thereafter being able to creep axially on the shaft. The securing methods commonly used do not generally permit this possibility as the preload usually must be applied with the use of shims, spacer sleeves, deformable sleeves, etc. In this way, there is no guarantee that the exactly applied preload will not be altered due to unknown degrees of deformation or infinite movements between the shaft and ring before the ring is secured, e.g. with a locking nut, which furthermore requires that the shaft is provided with a threaded portion.